An increasingly pressing problem in the area of waste disposal exists due to the rising costs of and limited space for landfills. Waste management companies and municipalities continue to search for viable alternatives to using landfills. These include recycling, incineration and composting. The common goal of waste treatment and recycling methods is to process waste safely, efficiently, and at a low cost, while using as much of the waste as possible to produce useful products. The more waste that can be transformed into usable products, the less waste that needs to be put in a landfill.
Composting is used to convert organic waste into a useable product. More specifically, this natural process reduces organic waste by converting it to natural fertilizer in the form of humus. One example of a specific type of composting is vermicomposting. In a typical vermicomposting process, worms are used to turn organic waste such as food and/or paper waste (e.g., low grade paper waste) into a premium soil supplement. The organic waste can be broken down by earthworms and micro-organisms resulting in a stable, nontoxic material with good structure. The material has potentially high economic value as a soil supplement for plant growth.
Both large and small scale composting systems exist. Large scale composting apparatuses occupy large amounts of space, use complicated machinery, and/or are labor intensive. Because they occupy a lot of space, such large scale composting apparatuses are typically at remote locations, far away from a school, factory, farm, restaurant, or other facility where organic waste is generated. Transporting the organic waste to a large scale composting facility at a remote location is costly. Unless very large quantities of organic waste are created, the cost of transporting the organic waste to the composting facility may be more than the cost of disposing of the organic waste in a landfill. This tends to discourage composting rather than encourage composting.
Small scale composting apparatuses could be used at the facilities where organic waste is generated. However, many existing small scale composting apparatuses are labor intensive, mechanically complicated, and/or do not have high enough compost production rates. For example, one commercially available composting apparatus is called the “Worm Wigwam”. This composting apparatus is in the form of a cylindrical container. Compostable material is fed through the top of the cylindrical container and the composted material passes out of the bottom of the cylindrical container. To help the composted material to pass out of the bottom of the cylindrical container, a bar is used to agitate the material near the bottom of the composting material, which rests upon a steel grate. The steel grate is located above the bottom of the container. To move the bar, a crank handle that is coupled to the container is turned around and around. In response, the bar moves across the bottom of the cylindrical container to agitate the composted material at the bottom. The agitated composted material then passes through holes in the steel grate that supports the composted material above the bottom of the container.
While an apparatus such as the Worm Wigwam can process organic waste at the facility producing the organic waste, a number of improvements could be made to the Worm Wigwam. For example, to move the bar and agitate composted material for harvesting, the user must turn the crank handle many times. This is very labor intensive. Also, the compost production rate of the Worm Wigwam is low. For example, in the Worm Wigwam, 1 to 2 inches of composted material might be harvested every day or so, from an area equal to the bottom region of the composting mass which is the same as the area of the cylindrical container. A typical Worm Wigwam may have a diameter of about 3 feet, so the volume of composted material produced would be about 0.58 to about 1.16 cubic feet per day. A facility such as a school, for example, may need to process much more waste than a single Worm Wigwam can process. Although more than one composting apparatus could be purchased to increase the compost production rate, this would undesirably increase the amount of space occupied by composting apparatuses and the amount of labor involved. In urban environments in particular, available space is difficult to find so that simply obtaining more composting apparatuses may not be a practical way to increase the composting rate.
Embodiments of the invention address these and other problems, collectively and individually.